B Why is it difficult to establish the number of species globally?___
A. There are too many species to count them all.
B. The number of species is constantly changing.
Currently, more species are appearing than are becoming extinct.
D. Human action has upset the balance of the natural environment.
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C Which of the following statements about snow match the information in the passage?___ ___
A. Snow is formed from ice.
B. Falling snow melts because of warm air around it.
C. Subzero temperatures are required for snow to fall.
D. Sleet develops at less than two degrees centigrade.
E. Dry snow falls in colder temperatures than wet snow.
D Which of the following statements are true according to the information in the passage?___ ___
A. There are insufficient sources of fresh water for human consumption.
B. Industrial pollution can affect both underground and river water.
C. There are numerous means by which water can become impure.
D. Rain is a safer source of water for human consumption than aquifers.
E. Water in reservoirs is chemically treated to remove harmful bacteria.
According to this reading, why did merchants have “culture-changing influence”?___
A. They found new ways to get from one country to another.
B. Many of the plants they sold were poisonous and killed off some populations.
C. They made it possible for cultures to develop new dishes.
D. They spread European cooking habits around the world.
Cinnamon, tomatoes, and saffron are mentioned to make the point that __________.
A. many of the new plants merchants introduced were from Asia
B. some strange-looking foods from odd sources were eventually accepted
C. nightshade was unfairly dreaded by Europeans
D. nearly every part of a plant can be turned into a kind of food
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